Among the early inhabitants of the island were Negritos, as well as Han Chinese and Malays.[5] They called the island "Buglas", a native word which is believed to mean "cut off".[4]

The Dumaguete Belfry was built in 1760s and 1870s to warn townsfolk of attacks by marauding pirates.

Spanish explorers on the expedition of Miguel Lopez de Legazpi first came to the island in April 1565. Legazpi dropped anchor in Bohol and sent his men to scout the island.[5] Because of the strong currents of the Tañon Strait between Cebu and Negros, they were carried for several days and forced to land on the western side of the island. They reported seeing many dark-skinned inhabitants, and they called the island "Negros" ("Negro" means "black" in Spanish). The island was sparsely settled at the time, except for a few coastal settlements including Ilog and Binalbagan. In 1571, Legaspi assigned encomiendas on the island to 13 of his men.[5]Augustinian friars began the Christianization of the island the next year. The island was administered as part of the jurisdiction of Oton until 1734 when it became a military district, and Ilog became the capital of the island. The capital was transferred to Himamaylan in 1795. Negros became a politico-military province in 1856 and the capital was transferred to Bacolod.

Due to its proximity to Mindanao, the south eastern coast of Negros was in constant threat from Moro marauders looking for slaves, and watchtowers were built to protect the Christian villages. The Moro raids and Negros Oriental's distance from the Negros capital in Bacolod induced 13 Recollectionist priests to petition for the division of the island in July 1876.[5] The island of Negros was then divided into the provinces of Negros Oriental and Negros Occidental by a royal decree executed by Governor General Valeriano Weyler on January 1, 1890. Dumaguete City was made the first capital of Negros Oriental. In 1892, Siquijor became a part of Negros Oriental, having previously been administered by Spain under the politico-military province of Bohol.

The Philippine Revolution reached the province in 1898, disrupting government functions but without bloodshed. Revolutionary troops in the province were composed mostly of farm laborers and other prominent people of the Negros Oriental province who were organized and led by Don Diego de la Viña. The Spanish government in Dumaguete was overthrown on November 24, 1898. Later, the Negros Occidental area under the leadership of Gen. Araneta only, in contrast to the Negros Oriental area under the leadership of Don Diego de la Viña, formed the Cantonal Republic of Negros, a separate government from the more familiar Malolos Republic established in Luzon.[6] In 1901 the Negros Oriental province was reorganized by the United States and a civil government was established with Demetrio Larena as governor. The American government made Siquijor a "sub-province" of Negros Oriental. Negros Oriental became a province under the American civil government on March 10, 1917. In 1934 Negros Oriental became a corregimiento, a separate military district. Under the American colonial government, transportation infrastructure was developed with improvements of roads and new bridges.[7]

During World War II, the province was invaded by Japanese forces and many residents were forced to flee to the mountains to escape.[8] Negros Island was liberated by combined Filipino & American troops with the local Negrosanon guerillas attacking the Japanese on August 6, 1945.

The 7th, 73rd, 74th and 75th Infantry Division of the Philippine Commonwealth Army was established 1942 to 1946 and the 7th Infantry Regiment of the Philippine Constabulary was active 1944 to 1946 at the Military General Headquarters in Negros Oriental. Started the engagements of the Anti-Japanese Imperial Military Operations in Negros Oriental 1942 to 1945 against the Japanese Imperial forces.

When the Filipino soldiers of the 7th, 73rd and 75th Infantry Division of the Philippine Commonwealth Army and 7th Infantry Regiment of the Philippine Constabulary was started the Liberation of Negros Oriental in 1945 and fought against the Japanese forces.

On September 17, 1971, Siquijor finally became an independent province by virtue of Republic Act No. 6396. (See Province of Siquijor)

Negros Oriental occupies the south-eastern half of the island of Negros, with Negros Occidental comprising the western half. It has a total land area of 5,402.30 km².[9] A chain of rugged mountains separates Negros Oriental from Negros Occidental. Unlike its sister province, which belongs to the Western Visayas region, Negros Oriental belongs to the Central Visayas region. Negros Oriental faces Cebu to the east across the Tañon Strait and Siquijor to the south-east. The Sulu Sea borders it to the south.

The province's topography is characterized by low, grooved mountain ranges which mostly lie close to the shoreline. At the southern end of the province is the Cuernos de Negros (Horns of Negros) stratovolcano which rises to a height of 1864 meters. At the northern end of the province is Mount Canlaon, the highest peak in the island with a height of 2465 meters and an active volcano. There are a few plateaus in the interior to the west of the province.

One of the landmarks of Dumaguete is the Dumaguete Bell Tower which stands next to the St Catherine of Alexandria Cathedral.[10] It once used to warn the city of impending pirate attacks.[11]

Negros Oriental has a tropical climate. Because of the mountain range running from the north to the south, the province has two types of climatic conditions.[12] The eastern part of the province is characterized by unpronounced maximum rainfall with a short dry season lasting from one to three months. The western half of the province is characterized by a distinct wet season and dry season.

Negros Oriental's total population as of the 2010 census is 1,286,666.[2] 34.5% of the population is concentrated in the six most populous component LGUs of Dumaguete City, Bayawan City, Tanjay City, Bais City, Canlaon City, and Guihulngan. The province's average population density is 208 persons per km², lower than the national average of 276 persons per km². Population growth per year is about 2.11%, higher than the national average of 1.92%.[17]

Cebuano (sometimes known as Visayan) is the main language of the province, spoken by 95% of the population. Hiligaynon is spoken by the remaining 5%, and is common in areas close to the border with Negros Occidental. Filipino and English are generally understood, and are used for official, literary, and educational purposes.

Negros Orienal has, for a long time, been a supplier of electricity to its neighboring provinces in the Visayas with its excess power capacity generated by the 192MW Palinpinon geothermal plant. This plant has recently been expanded with an additional 49MW capacity, bringing total power output of the province to over 240MW. Despite the huge power excess of the Province, other power sources such as hydro, wind and solar are being explored to provide additional power capacities that can be sold to neighboring areas.

Negros Oriental is emerging as a technological center in Central Philippines with its growing business process outsourcing (BPO) that has started to penetrate the Province's secondary cities, and other technology-related industries. Vehicle assembly is a growing industry in Amlan. Construction of mass housing and subdivisions is very evident in the periphery of Dumaguete, and is expected to spillover in the Province's secondary cities and fast growing municipalities. Other industries include water bottling, warehousing, and cold and dry storing. Retailing has penetrated urban areas outside Dumaguete with the entry of hypermarts in cities such as Bayawan, Tanjay and Bais. The town of Bacong, Dumaguete's neighbor in the south, hosts industrial plants geared for the local and export markets. Negros Oriental is also becoming a notable tourist destination in the Visayas.

Negros Oriental has a network of roads, including a national road that spans the circumference of Negros Island. National and provincial roads in the province total more than 900 kilometers, though only about half of these are paved.[19]

A large portion of residents do not own private vehicles, and are totally reliant on public transport. The main form of public transport between the cities and municipalities of the province largely consists of privately operated jeepneys that link major towns to rural areas. For short distances within a town, motorized tricycles (locally known as pedicabs) are available.

The Dumaguete Airport located in Sibulan is the province's only government-operated airport.[19] It is a domestic airport with multiple daily flights to and from Manila, served by Philippine Airlines and Cebu Pacific. Based on 2002 statistics, an average of 5,800 outgoing passengers and 5,700 incoming passengers pass through the airport every month. However, this airport is due for transfer to Bacong because of congestion in its current location. [19]

The primary seaport of the province is located in Dumaguete City. Additionally, there are five other seaports in the province classified as tertiary.[20]

Dumaguete City, the provincial capital, is known as a university town due to the existence of many universities and colleges in the city.[21] These universities include: Silliman University (1901), the oldest American established university in Asia;[22]St. Paul University Dumaguete (1904), the first Paulinian school in the Philippines; Negros Oriental State University (formerly NOTS-1927, EVSAT, CVPC); and Foundation University (1949). The Colegio de Sta. Catalina De Alejandria (COSCA), Negros Oriental High School (1902), Ramon Teves Pastor Memorial-Dumaguete Science High School (1986), Dumaguete City High School (1967), Catherina Cittadini (St. Louis) School, Holy Cross High School and St. Louis School-Don Bosco (1967) can be also found in the city. There are also institutions and colleges inside (e.g. Metro Dumaguete College, STI, Maxino College, PTC, AMA Computer College, Asian College) and outside the city.

Each town in Negros Oriental celebrates an annual town fiesta, usually dedicated to a saint who is the patron of the town. In some of the larger towns, there are particular fiestas for specific neighborhoods or barangays.

Additionally, the Buglasan Festival, which was revived in 2001, is celebrated annually in October in the provincial capital of Dumaguete and is hailed as Negros Oriental's "festival of festivals".[23] It is a week-long celebration where you can see unique booths of each town and city in Negros Oriental featuring their native products and tourist attractions. The highlight of the occasion is the float parade and street dancing competition.[24]